Odo I, Margrave of the Saxon Ostmark

Count Christian, probably a scion of the Billung dynasty, had married Hidda (d. 970), a sister of Gero, margrave of the vast marca Geronis in the lands settled by Polabian Slavs.

[citation needed] Odo spent the first years of his rule subduing the Slavic tribes settling in the eastern parts of the Saxon Ostmark.

The West Slavic Polans had established a state east of the Saxon marches and, aiming to advance into the Pomeranian lands north of the Warta river, had reached an agreement with late Margrave Gero and Emperor Otto I: Mieszko's ducal title was confirmed and the Polans paid a recurring tribute to the emperor, which was collected by Margrave Odo.

[citation needed] In 983, Odo took part in the attempts to suppress the Great Slav Rising of the Polabian Lutici tribes, but was not able to prevent the loss of the Saxon Northern March.

Siegfried again appeared as a count from 1015, when he claimed the Saxon Ostmark from Gero's son Thietmar IV and allied with Duke Mieszko II of Poland in the German–Polish War.